The collector system of the present invention, basically includes a semi-cylindrical or other optical concentrating means which can take any of a wide variety of cross sectional shapes such as parabolas, hyperbolas, catenaries, semi-ellipses, higher order curves or composite surfaces made up of segments of simple curves, including planes. Such shapes can be used in semi-cylindrical reflectors of any required length or to form circular mirrors or mirrors of any desired shape.
The collector elements are made of metal, and coated with a good radiation absorber, preferably black, by any known process, the simplest of which consists of a black coated metal strip in intimate thermal contact with a pipe, tube duct or other channel through which the heat-transfer fluid flows. These range in complexity of manufacture from simple lengths of pipe or tubing, soldered or otherwise fastened to the black metal strips or plates, either flat or curved to conform to the shape of the pipe, thereby improving the thermal contact, to laminate strips with internal fluid channels between the laminae, or extrusions combining the fluid channels and collector plates in one piece.
Various designs exist for improving the collection efficiency and/or concentration of the radiation by proper orientation of the system of the present invention. Instead of continuous orientation, with the requisite sensors, controls and motor-drive mechanism, the necessary performance may be achievable by means of a monthly, for example, change in the collector angle and the proper design and construction of the collector elements.
Therefore, one of the principal objects of the present invention is to provide a solar energy collector device comprising an elongated optical concentrating member, generally semi-cylindrical in cross section and having a reflective inner surface, and a multipartite collector that sequentially heats the heat-transfer fluid carried in pipes, tubes or ducts associated with the multipartite collector in a manner so as to improve the instantaneous and/or average energy collection efficiency of the device relative to a single-element collector.
A further object of this invention is to provide a bank of said solar energy collector devices in assembly.
Yet another object of this invention is to provide a solar energy collector device in which the energy is concentrated, permitting the attainment of somewhat higher temperatures than in a conventional flat-plate collector.
Another object of this invention is to provide a solar energy collector device which results in lower energy losses and provides for insulation more effectively than in a flat-plate collector while permitting higher temperatures.
A still further object of the present invention is to provide a solar energy collector device which operates efficiently with no required adjustment of tilt angle, as in most focusing collectors.